DS87C550 High-Speed Microcontroller User’s Guide Supplement
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Interrupt Priority (IP)
7
6
5
4
3
2
1
0
SFR B8h
-
PAD
PS1
PS0
PT1
PX1
PT0
PX0
-
RW-0
RW-0
RW-0
RW-0
RW-0
RW-0
RW-0
R=Unrestricted Read, W=Unrestricted Write, -n=Value after Reset
Bit 7
Reserved. Read data is indeterminate.
PAD
Bit 6
A/D Interrupt.
This bit controls the priority of the A/D Converter interrupt.
0 = A/D interrupt priority is determined by the natural priority order.
1 = A/D interrupt is a high priority interrupt.
PS1
Bit 6
Serial Port 1 Interrupt.
This bit controls the priority of the serial port 1
interrupt.
0 = Serial port 1 priority is determined by the natural priority order.
1 = Serial port 1 is a high priority interrupt.
PS0
Bit 4
Serial Port 0 Interrupt.
This bit controls the priority of the serial port 0
interrupt.
0 = Serial port 0 priority is determined by the natural priority order.
1 = Serial port 0 is a high priority interrupt.
PT1
Bit 3
Timer 1 Interrupt.
This bit controls the priority of Timer 1 interrupt.
0 = Timer 1 is determined by the natural priority order.
1 = Timer 1 is a high priority interrupt.
PX1
Bit 2
External Interrupt 1.
This bit controls the priority of external interrupt 1.
0 = External interrupt 1 is determined by the natural priority order.
1 = External interrupt 1 is a high priority interrupt.
PT0
Bit 1
Timer 0 Interrupt.
This bit controls the priority of Timer 0 interrupt.
0 = Timer 0 is determined by the natural priority order.
1 = Timer 0 is a high priority interrupt.
PX0
Bit 0
External Interrupt 0.
This bit controls the priority of external interrupt 0.
0 = External interrupt 0 is determined by the natural priority order.
1 = External interrupt 0 is a high priority interrupt.
